code: def mu_law_decoding(signal_mu, quantization_channels):
      """Decode mu-law encoded signals based on mu-law companding. Also called mu-law expanding.
  
      See `Wikipedia <https://en.wikipedia.org/wiki/Μ-law_algorithm>`_ for more details.
  
      Args:
          signal_mu (int `Tensor`): mu-encoded signal to decode
          quantization_channels (positive int): Number of channels. For 8-bit encoding, use 256.
  
      Returns:
          signal (float `Tensor`): decoded audio signal
      """
      mu = quantization_channels - 1.0
      signal_mu = K.cast_to_floatx(signal_mu)
  
      signal = (signal_mu / mu) * 2 - 1.0
      signal = (
          tf.math.sign(signal)
          * (tf.math.exp(tf.math.abs(signal) * tf.math.log1p(mu)) - 1.0)
          / mu
      )
      return signal
  
file_path: kapre/kapre/backend.py
imports: from tensorflow.keras import backend
  import tensorflow
  import numpy
  import librosa
label_desc: Use image node_id 7 for calling a global function with example usage: mu_law_decoding(signal_mu, quantization_channels) and returns: signal